Light is incident normally on two narrow parallel slits a distance of 1.00 mm apart. A screen is placed a distance of 1.2 m from the slits. The distance on the screen between the central maximum and the centre of the n=4 bright spot is measured to be 3.1 mm.
(a) Determine the wavelength of light.
(b) This experiment is repeated in water. Suggest how the distance of 3.1 mm would change, if at all.